Joint optimization of a radio access network and a distributed antenna system

ABSTRACT

Certain features relate to systems and methods for jointly optimizing a radio access network (RAN) and distributed antenna system (DAS). A joint RAN-DAS self-optimizing network (SON) entity can determine target parameters based on parameters specific to the DAS and parameters specific to the RAN. The joint RAN-DAS-SON entity can optimize the RAN and DAS using the target parameters. Jointly optimizing the RAN and the DAS can improve the capacity characteristics, coverage characteristics, or the performance characteristics of the RAN and DAS. In some aspects, the joint RAN-DAS-SON entity can optimize the RAN and DAS by re-allocating power levels of downlink signals transmitted by remote units of the DAS to compensate for underutilized carrier signals in situations of low traffic load.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/431,263, filed Feb. 13, 2017, and titled “Joint Optimization of aRadio Access Network and a Distributed Antenna System,” which is acontinuation of U.S. patent application Ser. No. 14/760,402, filed Jul.10, 2015, and titled “Joint Optimization of a Radio Access Network and aDistributed Antenna System,” which is a U.S. national phase under 35U.S.C. 371 of International Patent Application No. PCT/US2015/015999,titled “Joint Optimization of a Radio Access Network and a DistributedAntenna System,” and filed Feb. 16, 2015, which claims priority to U.S.Provisional Application Ser. No. 61/942,800, filed Feb. 21, 2014, andtitled “Jointly Managing the Operation and Configuration of DistributedAntenna Systems and Radio Access Network Systems,” wherein the contentsof all of the foregoing applications are hereby incorporated herein byreference.

TECHNICAL FIELD

The disclosure relates generally to telecommunications and, moreparticularly (although not necessarily exclusively), to joint managementand optimization of a radio access network and a distributed antennasystem.

BACKGROUND

A distributed antenna system (DAS) can include one or more head-endunits and multiple remote units coupled to each head-end unit. A DAS canbe used to extend wireless coverage in an area. Head-end units can beconnected to one or more base stations of a radio access network (RAN).Each base station can be part of a separate node of the RAN. A head-endunit can receive downlink signals from the base station and distributedownlink signals in analog or digital format to one or more remoteunits. The remote units can transmit the downlink signals to userequipment devices within coverage areas serviced by the remote units. Inthe uplink direction, signals from user equipment devices may bereceived by the remote units. The remote units can transmit the uplinksignals received from user equipment devices to a head-end unit. Thehead-end unit can transmit uplink signals to the serving base stations.The DAS may thus provide coverage extension for communication signalsfrom the RAN nodes.

The RAN and DAS may be separately managed and optimized via respectiveoperations and management self-optimizing network (SON) units. A DAS SONunit, for example, can use parameters and counters specific to the DAS.The DAS SON unit can be fully separated from the RAN equipment. Theresult of a separate DAS SON unit from RAN equipment is that anymodification to the configuration of the RAN nodes can have anunexpected impact on the operation of the DAS. Similarly, anymodification to the configuration of the DAS can have an unexpectedimpact on the RAN nodes. RAN and DAS system optimization cannot bejointly performed on DAS and RAN nodes with a DAS SON unit separatedfrom the RAN nodes.

SUMMARY

In one aspect, a method is provided. The method can include collecting,from a radio access network, a first set of operations and managementparameters. The method can also include collecting, from a distributedantenna system, a second set of operations and management parameters.The method can further include determining, by a processing device,target operations and management parameters for jointly optimizing theradio access network and the distributed antenna system. The method canalso include jointly optimizing the radio access network and thedistributed antenna system based on the first set of operations andmanagement parameters, the second set of operations and managementparameters, and the target operations and management parameters.

In another aspect, a joint radio access network-distributed antennasystem-self-optimizing network (RAN-DAS-SON) entity is provided. Thejoint RAN-DAS-SON entity can include first operations and managementinterface configured to receive a first set of operations and managementparameters from one or more nodes of a radio access network. The jointRAN-DAS-SON entity can also include a second operations and managementinterface configured to receive a second set of operations andmanagement parameters from a head-end unit of a distributed antennasystem. The joint RAN-DAS-SON entity can further include an analysismodule configured to determine target operations and managementparameters for the radio access network and the distributed antennasystem. The analysis module can also jointly optimize the radio accessnetwork and the distributed antenna system based on the first set ofoperations and management parameters, the second set of operations andmanagement parameters, and the target operations and managementparameters.

In another aspect, joint radio access network-distributed antennasystem-self-optimizing network (RAN-DAS-SON) entity is provided. Thejoint RAN-DAS-SON entity can include a first operations and managementinterface configured to receive a first set of operations and managementparameters from one or more nodes of a radio access network. The jointRAN-DAS-SON entity can also include a second operations and managementinterface configured to receive a second set of operations andmanagement parameters from a head-end unit of a distributed antennasystem. The joint RAN-DAS-SON entity can further include a processingdevice. The joint RAN-DAS-SON entity can also include a memory devicehaving program code stored thereon. Upon execution by the processingdevice, the program code is configured to perform operations comprisingdetermining target operations and management parameters for the radioaccess network and the distributed antenna system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example of a radio access network (RAN)and distributed antenna system (DAS) architecture according to oneaspect of the present disclosure

FIG. 2 is a block diagram of an example of a joint RAN-DASself-optimizing network (SON) entity according to one aspect of thepresent disclosure.

FIG. 3 is a flowchart depicting a process for jointly optimizing a RANand a DAS according to one aspect of the present disclosure.

FIGS. 4A-4B are tables depicting examples of power allocation andre-allocation across downlink carrier signals from RAN nodes and aremote unit according to one aspect of the present disclosure.

DETAILED DESCRIPTION

Certain aspects and features are directed to methods and systems forjointly managing and optimizing the operation and configuration of adistributed antenna system (DAS) and a radio access network (RAN). Forexample, a joint RAN-DAS self-optimizing network (SON) entity can becommunicatively coupled to the DAS head-end unit and one or more nodesof the RAN. The joint RAN-DAS-SON entity can receive operations andmanagement (O&M) parameters specific to the RAN and O&M parametersspecific to the DAS. Based on the DAS O&M parameters and RAN O&Mparameters, the joint RAN-DAS-SON entity can determine target values forO&M parameters, which can indicate optimal optimization settings for theRAN and DAS. For example, the optimal optimization settings can includesettings to tune the RAN and DAS for optimal coverage, capacity, orperformance. In some aspects, optimization settings can includeadjustments for the uplink/downlink gain of signals transmitted by theRAN or DAS to compensate for detected noise within the RAN and DAS. Inother aspects, optimization settings can include re-allocating powerlevels of downlink signals transmitted by RAN nodes to account forchanging traffic conditions. Other settings to tune the RAN and DAS foroptimal coverage, capacity, or performance are also possible.

Jointly optimizing the RAN and a DAS through a joint RAN-DAS-SON entitycan facilitate communication between RAN nodes and DAS head-end unitsand reduce delays caused by measuring and sending performance databetween the DAS and the RAN. For example, without a joint RAN-DAS-SONentity, a base station in a RAN can compensate for uplink noisegenerated by the DAS by measuring for uplink noise offline first, andthen separately adjusting uplink/downlink gain to compensate for theuplink noise through the O&M system of the base station. A jointRAN-DAS-SON entity can receive performance indicators indicating uplinknoise level from the RAN and DAS and in response send instructions tothe DAS head-end unit to modify the uplink gain or a DAS node to modifythe downlink gain. Similarly, the joint RAN-DAS-SON entity can adjustfor signal delay introduced by the DAS.

For example, the DAS can measure value of the delay introduced betweenthe head end and the remote unit in both downlink and the uplinkdirections. This value can be reported to the joint RAN-DAS-SON entitywhich in turn can send an O&M command to the base station (i.e. the RANNode). This command can be the Cell Radius O&M parameter used in thebase station to configure the maximum expected delay in the cell served.The optimal value of the Cell Radius parameter can be calculated by theSON entity as follows:[DAS roundtrip (downlink+uplink) delay+estimated over-the-air roundtripdelay (due to propagation over max distance between the remote unit anduser terminal)]*Light Speed/2. This formula is valid by assuming totalDL delay=total UL delay.

Jointly optimizing the RAN and DAS through a joint RAN-DAS-SON entitycan also make performance data of the RAN available to the DAS. Thejoint RAN-DAS-SON entity can detect changes to RAN performance data andmake corresponding optimizations to DAS settings to tune the DAS tooptimal performance characteristics.

These illustrative aspects and examples are given to introduce thereader to the general subject matter discussed here and are not intendedto limit the scope of the disclosed concepts. The following sectionsdescribe various additional features and examples with reference to thedrawings in which like numerals indicate like elements, and directionaldescriptions may be used to describe the illustrative aspects but, likethe illustrative aspects, should not be used to limit the presentdisclosure.

FIG. 1 is a logical block diagram depicting an example of a RAN-DASarchitecture with a joint RAN-DAS-SON entity suitable for implementingthe subject matter described herein. The RAN-DAS architecture caninclude a DAS with remote units 106 a-d (each remote unit labeled “DASRU” in FIG. 1) communicatively coupled to a DAS head-end unit 102. Thehead-end unit 102 can include an O&M application programming interface(API) 104, which can be used to provide DAS O&M parameters to a jointRAN-DAS-SON entity 108. Non-limiting examples of DAS O&M parameters caninclude downlink/uplink gain settings, frequency allocations, sectormapping settings, maximum input/output power levels, temperaturecontrols, and measured interference levels.

The RAN-DAS architecture can also include a RAN with multiple operators.Each operator can have multiple RAN nodes associated with multipletechnologies, sector identifiers, and carrier frequencies. As shown inFIG. 1, RAN operator A can include RAN nodes 118 a-d communicativelycoupled to a core network 130 a for operator A. RAN nodes 118 a-d caneach include an O&M API 122 a-d for communicating RAN O&M parameterswith the joint RAN-DAS-SON entity 108. Non-limiting examples of RAN O&Mparameters can include base station software stack control andmonitoring parameters, radio front end processing parameters, mediaaccess control scheduler settings, radio resource management settings,and transport plane settings. RAN operator A can also include an elementmanagement system (EMS)/network management system (NMS) entity 126 acommunicatively coupled to the joint RAN-DAS-SON entity 108. Similarly,RAN operator B can include RAN nodes 120 a-d communicatively coupled toa core network 130 b for operator B. RAN nodes 120 a-d can also includeO&M APIs 124 a-d for communicating RAN O&M parameters to the jointRAN-DAS-SON entity 108. RAN operator B can also include an EMS/NMSentity 126 b communicatively coupled to the joint RAN-DAS-SON entity108. While FIG. 1 depicts joint RAN-DAS SON entity 108 separate from theRAN and DAS for illustrative purposes, in other aspects, the jointRAN-DAS SON entity 108 can be included in one of the RAN nodes 118 a-d,120 a-d or in the head-end unit 102.

The EMS/NMS entities 126 a-b can include an EMS and an NMS specific toeach respective operator. The EMS/NMS entities 126 a-b can managenetwork elements of the respective operator networks. For example,EMS/NMS entities 126 a-b can manage network administration tasks,identify network issues within the respective RAN, and manage thecapacity of the RAN and identify areas of data congestion within eachrespective RAN. Each of the RAN nodes 118 a-d and 120 a-d can include abase station for providing downlink communications to the DAS head-endunit 102. The base stations of each respective RAN node 118 a-d and 120a-d can also receive uplink communications from the head-end unit 102and provide the uplink communications to respective core networks 130a-b.

The joint RAN-DAS-SON entity 108 can receive RAN O&M parameters from RANnodes 118 a-d, 120 a-d via a RAN O&M API 112. The joint RAN-DAS-SONentity 108 can also receive DAS O&M parameters via a DAS O&M API 110.The joint RAN-DAS-SON entity 108 can also receive communications fromthe EMS/NMS entities 126 a-b via an EMS/NMS interface 114. In someaspects, the joint RAN-DAS-SON entity 108 can receive EMS/NMS commandsdirectly from RAN nodes 118 a-d and 120 a-d.

Based on the received RAN O&M parameters and DAS O&M parameters, thejoint RAN-DAS-SON entity 108 can determine target O&M parameters foroptimal configuration of elements of the RAN and DAS. Target O&Mparameters can include various parameters for jointly optimizing the RANand DAS. The target O&M parameters can include optimal configurationsettings to optimize coverage characteristics, capacity characteristics,or performance characteristics of the RAN and DAS. For example, each ofthe RAN operators can have different key performance indicators thatspecify target performance guidelines such as network capacityrequirements and minimum quality of service requirements. Each operatorcan adopt a specific policy on the visible/configurable parameters. Inone aspect, the target O&M parameters determined by the jointRAN-DAS-SON entity 108 can be provided to the DAS head-end unit 102 andthe individual RAN nodes 118 a-d, 120 a-d to modify RAN and DAS systemparameters to ensure that the key performance indicators of thedifferent operators are met. Further, the joint RAN-DAS-SON entity 108can jointly manage the RAN and DAS to minimize the impact on oneoperator network (e.g., RAN nodes 120 a-d) due to configuration changesin the other operator network (e.g, RAN nodes 118 a-d). Further, thejoint RAN-DAS-SON entity 108 can modify parameters specific to the DAShead-end unit 102 in order to optimize the DAS due to changes in the RANconfiguration. Parameters specific to the head-end unit 102 that can beadjusted include the gain of signals transmitted by the head-end unit102.

In some aspects, target O&M parameters jointly configured by the jointRAN-DAS-SON entity 108 can include values to adjust the uplink gain ofthe DAS head-end unit 102. For example, the uplink noise from a RAN node118 can be used as a reference parameter to adjust the DAS uplink gain.The DAS head-end unit 102 can report the generated uplink noise power atthe input port of the RAN node 118, and the joint RAN-DAS-SON entity 108can adjust the uplink gain of the DAS head-end unit 102 based on theuplink noise power reference of the RAN node 118. If the head-end unit102 uplink noise power exceeds the uplink noise power reference of theRAN node 118 by x dB due to the current DAS head-end unit 102 uplinkgain, then the joint RAN-DAS-SON entity 108 can reduce the head-end unit102 UL gain by x dB.

Another RAN O&M parameter that the joint RAN-DAS-SON entity 108 can useto optimize the DAS head-end unit 102 uplink gain is the P0nom targetparameter of the RAN Node 118. In the LTE wireless communicationstandard, the P0nom target parameter corresponds to the reference uplinknominal power. A target power level at the input of a DAS remote 106 canalso be defined and available at the joint RAN-DAS-SON entity 108. Thejoint RAN-DAS-SON entity 108 can set the uplink gain of the DAS head-endunit 102 so that:target DAS remote unit input power+DAS head-end unit uplink gain=P0nomtarget

In another aspect, the target uplink signal to interference-plus-noiseratio (SINR) of the RAN node 118 can be used by the joint RAN-DAS-SONentity 108 in order to optimize the number of DAS remote units 106connected to the same RAN node 118 (i.e. the same sector). The number ofremote units 106 connected to the same RAN node 118 is a target O&Mparameter that can be referred to as the DAS simulcast factor. If thetarget uplink SINR of the RAN node 118 cannot be met due to excessiveuplink noise from the DAS, the joint RAN-DAS-SON entity 108 can reducethe DAS simulcast factor and send a command to the DAS head-end unit 102instructing the head-end unit 102 to reduce the DAS simulcast factor.

For example, if the target uplink SINR is equal to x dB, and the currentuplink SINR is equal to x−3 dB, then the joint RAN-DAS-SON entity 108can instruct the DAS head-end unit 102 to reduce the simulcast factor byhalf (i.e. to reduce by half the number of remote units 106 connected tothe same sector). Reducing the DAS simulcast factor by half can increasethe uplink SINR of the RAN node 118 by 3 dB and meet the target.

In additional aspects, the RAN O&M parameter indicating the number ofactive antennas of the RAN node 118 can be used by the joint RAN-DAS-SONentity 108 to optimize the number of active DAS remote units 106. If theRAN node 118 reports that a secondary antenna port (e.g. in case of a2×2 MIMO configuration) is not active, then the joint RAN-DAS-SON entity108 can instruct the DAS head-end unit 102 to shut down the DAS remoteunits 106 a-d communicatively linked to the secondary antenna port ofthe RAN node 118. In addition to shutting down the DAS remote units 106a-d communicatively linked to the secondary antenna port, the DShead-end unit 102 can also shut down any other DAS module related to thesecondary radio path.

In additional aspects, the target O&M parameter that the jointRAN-DAS-SON entity 108 can configure includes values to adjust thedownlink gain of the head-end unit 102. For example, the RAN node 118can report the transmission output power of the RAN node 118 for a givencarrier to the joint RAN-DAS-SON entity 108. The joint RAN-DAS-SONentity 108 can also obtain information from the RAN node 118 regardingthe desired target power for the given carrier as transmitted by the DASremote unit 106. The joint RAN-DAS-SON entity 108 can configure the DAShead-end unit 102 downlink gain in order to reach the target outputpower level at the remote unit 106 as follows:target DAS remote unit output power=RAN node transmission power+DASdownlink gain.

The joint RAN-DAS SON entity 108 can also configure the DAS head-endunit 102 downlink gain based on the output power and target output powerof a pilot signal. For example, the RAN node 118 can also report to thejoint RAN-DAS-SON entity 108 the output power of the pilot signal fromthe RAN node 118. The DAS head-end unit 102 can report the target outputpilot power at the DAS remote unit 106. The joint RAN-DAS SON entity 108can configure the DAS head-end unit 102 downlink gain according to thesame formula above. In some aspects, the optimal setting for the DAShead-end unit 102 downlink gain can also be a negative value, in whichcase the joint RAN-DAS SON entity 108 can attenuate the downlink gain ofthe head-end unit 102.

In other aspects, the Low Noise Amplifier (LNA) gain in the uplink pathof the RAN node 118 can be reported to the joint RAN-DAS SON entity 108.In order to optimize the uplink path performance of the RAN and DAScombined system, the joint RAN-DAS SON entity 108 can switch off the LNAof the RAN node 118 and set the uplink gain of the DAS head-end unit 102equal to the gain of the LNA of the RAN node 118. In some aspects, aTower Mounted Amplifier (TMA) gain setting may be available at the RANnode 118. The joint RAN-DAS SON entity 108 can set the uplink gain ofthe TMA of the RAN node 118 to a value equal to:uplink noise rise at the RAN node due to the DAS+(uplink-downlink) gainimbalance of the DAS

In additional aspects, the RAN node 118 can report to the joint RAN-DASSON entity 108 information related to the frequency, technology, channelbandwidth, Mobile Country Code, Mobile Network Code of the radiated cellsignals, including other information the RAN node 118 may broadcast tothe network. The joint RAN-DAS SON entity 108 can relay this informationto the DAS head-end unit 102, and to the DAS controller within thehead-end unit 102 more specifically.

The RAN node 118 can also provide RAN O&M parameters includinginformation indicating the current Transmission Mode (TM) to the jointRAN-DAS SON entity 108. For example, the TM can correspond to variousantenna transmission configurations including SISO, MIMO TX Diversity,or MIMO Spatial Multiplexing (open loop or closed loop). If the RAN node118 operates in a closed loop TM, then the RAN node 118 also may alsoprovide the Pre-coding Matrix Indicator (PMI) in operation, whichdepends on the type of phase shift (e.g., +−90, +−180 degrees, orothers) the RAN node 118 applies to the transmitted signals. The jointRAN-DAS SON entity 108 can report the parameters including the TM andthe PMI to the DAS head-end unit 102, and to the DAS controller morespecifically. The DAS head-end unit 102 can apply another phase-shift tothe received signals according to the phase shift applied by the RANnode 118. By coherent combining o the phase shifted signals at the DAShead-end unit 102, the desired signal strength can be maximized and theundesired signals can be canceled.

In additional aspects, the traffic load on a given cell can be alsoreported by the RAN node 118 to the joint RAN-DAS SON entity 108. Incase the reported traffic load is higher than a given threshold for agiven DAS simulcast configuration (i.e. the number of DAS remote units106 radiating the same cell signal), then the joint RAN-DAS SON entity108 can instruct the DAS head-end unit 102 to reduce the DAS simulcastfactor (e.g., assign fewer remote units to the same cell signal). TheDAS head-end unit 102 can use a signal switching function to route thecell signal to different remote units 106.

In another aspect, instead of determining the target O&M parameters, thejoint RAN-DAS-SON entity 108 can operate in a “slave” mode by forwardingRAN O&M parameters and DAS O&M parameters to the EMS/NMS entities 126a-b. The EMS/NMS entities a-b can determine optimal configurationsettings for the RAN and DAS and provide instructions on theconfiguration settings to the joint RAN-DAS-SON entity 108. Using theinstructions from the EMS/NMS entities 126 a-b, the joint RAN-DAS-SONentity 108 can optimize the RAN and DAS to optimize coveragecharacteristics, capacity characteristics, or performancecharacteristics.

FIG. 2 is a block diagram depicting an example of a joint RAN-DAS-SONentity 108 according to one aspect. The joint RAN-DAS-SON entity 108 caninclude a system bus 204 that can communicatively couple an analysismodule 210 with the RAN O&M API 112, and a DAS O&M API 110.

The analysis module 210 can include a processing device 214 and a memorydevice 212. The processing device 214 can include any device suitablefor executing program instructions to control operation of the jointRAN-DAS-SON entity 108. Examples of processing device 214 include amicroprocessor, an application-specific integrated circuit (“ASIC”), afield-programmable gate array (“FPGA”), or other suitable processor. Theprocessing device 214 may include one processor or any number ofprocessors. The memory device 212 can include any non-transitory mediafor storing program code defining the operations of the jointRAN-DAS-SON entity 108. Non-limiting examples of memory device 212 caninclude read-only memory (ROM), random-access memory (RAM), opticalstorage, magnetic storage, flash memory, or any other medium from whichthe processing device 214 can read program code.

The memory device 212 can include program code defining instructionsthat, when executed by the processing device 214, cause the jointRAN-DAS-SON entity 108 to switch between a “master” mode, a “slave”mode, and a “hybrid” mode. While operating in a “master” mode, the jointRAN-DAS-SON entity 108 can determine target O&M parameters based onreceived DAS O&M parameters and RAN O&M parameters. The target O&Mparameters can be provided as instructions to the appropriate RAN nodes118 a-d, 120 a-d or DAS head-end unit 102. While operating in a “slave”mode, the joint RAN-DAS-SON entity 108 can forward DAS O&M parametersand RAN O&M parameters to EMS/NMS entities 126 a-b. The jointRAN-DAS-SON entity 108 can also forward instructions on optimalconfiguration received from the EMS/NMS entities 126 a-b to RAN nodes118 a-d, 120 a-d, and to DAS head-end unit 102 via the RAN O&M API 110and the DAS O&M API 112, respectively. In a “hybrid” mode, a portion ofthe O&M target parameters can be determined by the joint RAN-DAS-SONentity 108 and a second portion of the O&M target parameters can bedetermined by the EMS/NMS entities 126 a-b and forwarded to theappropriate RAN nodes 118 a-d, 120 a-d or DAS head-end unit 102. In someaspects, each operator of the RAN can specify different optimizationalgorithms for the joint RAN-DAS-SON entity 108. In this context, eachoperator can select which target O&M parameters should be determined atthe joint RAN-DAS-SON entity 108 and which target O&M parameters can becentrally managed at the EMS/NMS entities 126 a-b

FIG. 3 is a flowchart depicting a process 300 for jointly optimizing aRAN and DAS architecture based on collected O&M parameters. In block310, the joint RAN-DAS-SON entity 108 can collect a first set of O&Mparameters. For example, the joint RAN-DAS-SON entity 108 can collectRAN O&M parameters from each of the RAN nodes 118 a-d, 120 a-d via theRAN O&M API 112 included in the joint RAN-DAS-SON entity 108. In someaspects, the joint RAN-DAS-SON entity 108 can request each RAN node 118a-d, 120 a-d to a set of RAN O&M parameters at a particular point intime. In other aspects, each base station in the RAN nodes 118 a-d, 120a-d can periodically transmit measured RAN O&M parameters to the jointRAN-DAS-SON entity 108. As mentioned above, RAN O&M parameters from aparticular RAN node 118 a can include various control parametersspecific to the operator for the RAN node 118 a.

In block 320, the joint RAN-DAS-SON entity 108 can collect a second setof O&M parameters. For example, the joint RAN-DAS-SON entity 108 cancollect DAS O&M parameters from the DAS head-end unit 102 similar to thesteps described with respect to block 310. As mentioned above, DAS O&Mparameters can include control and signaling parameters specific to theDAS.

The joint RAN-DAS-SON entity 108 can determine target O&M parametersbased on the first set of O&M parameters and the second set of O&Mparameters, as shown in block 330. Target O&M parameters can includeoptimal configuration settings for jointly configuring the RAN and theDAS. For example, the first set of O&M parameters (e.g., RAN O&Mparameters) may include key performance indicators indicating networkperformance guidelines and minimum quality of service requirements. Thejoint RAN-DAS-SON entity 108 can determine the target O&M parametersthat would meet the performance guidelines specified by the keyperformance indicators. As another example, the first set of O&Mparameters can indicate measured uplink noise detected by base stationsat RAN nodes 118 a-d, 120 a-d. In response, the joint RAN-DAS-SON entity108, via the analysis module 210, can determine target O&M parameters tocompensate for the uplink noise. Target O&M parameters to compensate foruplink noise can include instructions for increased gain at the head-endunit 102. Similarly, the joint RAN-DAS-SON entity 108 can determinetarget O&M parameters and provide instructions to the base stations atRAN nodes 118 a-d, 120 a-d to adjust downlink gain to compensate fordownlink noise measured at the head-end unit 102.

In another aspect, the joint RAN-DAS-SON entity 108 can be configured tooperate in a “slave” mode and forward the first set of O&M parametersand second set of O&M parameters to the EMS/NMS entities 126 a-b. TheEMS/NMS entities 126 a-b can determine the target O&M parameters andgenerate instructions regarding optimizing the RAN and DAS to meet thetarget O&M parameters.

Based on the first set of O&M parameters, second set of O&M parameters,and the target O&M parameters, the joint RAN-DAS-SON entity 108 canjointly optimize the RAN and the DAS, as indicated in block 340. Forexample, while the joint RAN-DAS-SON entity 108 operates in a “master”mode, the analysis module 210 can determine instructions for optimizingcharacteristics of the RAN and DAS to obtain the target O&M parameters.The joint RAN-DAS-SON entity 108 can provide the instructions regardingthe target O&M parameters to the RAN nodes 118 a-d, 120 a-d to optimizeaspects of the RAN. The joint RAN-DAS-SON entity 108 can also providethe instructions regarding the target configuration settings to the DAShead-end unit 102 to optimize aspects of the DAS. As discussed above,jointly optimizing the RAN and the DAS can improve the capacitycharacteristics, coverage characteristics, or the performancecharacteristics of the RAN and DAS. When the joint RAN-DAS-SON entity108 operates in a “slave” mode, the joint RAN-DAS-SON entity 108 canjointly optimize the RAN and DAS by forwarding instructions from theEMS/NMS entities 126 a-b to the RAN nodes 118 a-d, 120 a-d and thehead-end unit 102.

Optimizing the RAN and DAS by Re-Allocating Power Levels of DownlinkCarrier Signals

In some aspects, the joint RAN-DAS-SON entity 108 can optimize the RANand DAS by re-allocating power levels across downlink carriers based onlow traffic conditions detected on one or more downlink carriers. Forexample, RAN nodes 118 a-d, 120 a-d can each transmit a differentdownlink carrier signal at varying power levels defined duringinitialization of the DAS. The power levels of the individual downlinkcarrier signals can be independently calculated to meet specific keyperformance indicators for remote units 106 a-d. For example, keyperformance indicators for remote units 106 a-d may specify that thedownlink carrier signals are transmitted at a minimum pilot power level.Each remote unit 106 a-d can transmit the multiple carrier signals touser devices.

During operation of the RAN and DAS, however, low traffic conditions mayexist for one or more of the downlink carrier signals, such that some ofthe allocated power is unused. Low traffic conditions can thus result ininefficient power distribution due to unused bandwidth. When a givendownlink carrier signal is associated with a low traffic load, the jointRAN-DAS-SON entity 108 can re-distribute the power allocation across thedownlink carriers to optimize the RAN and DAS.

For example, FIGS. 4A and 4B are tables depicting an example of powerallocation and re-allocation across four downlink carrier signals fromRAN nodes 118 a-d and remote unit 106. FIG. 4A depicts the power levelper downlink carrier signal provided by RAN nodes 118 a-d, each RAN node118 a-d respectively transmitting one carrier signal 402 a-d. Duringinitialization of the RAN and DAS, initial power allocation for thesignals transmitted by RAN nodes 118 a-d can be evenly divided as shownin row 404, each RAN node 118 a-d transmitting 43 decibel-milliwatts(dBm) when transmitting for full traffic load. During operation of theRAN and DAS, one carrier signal 402 a may exhibit no traffic load, inwhich case RAN node 118 a can transmit carrier signal 402 a at a reducedpower level of 33 dBm.

FIG. 4B depicts a table showing example power levels of the downlinkcarrier signals 402 a-d transmitted by remote unit 106. Row 406 depictspower level per carrier signal as transmitted by remote unit 106 uponinitialization of the RAN and DAS. As in FIG. 4A, initial powerallocation for signals transmitted by remote unit 106 can be evenlydivided, remote unit 106 transmitting all four carrier signals 402 a-dat 24 dBm. Row 406 also indicates that the remote unit 106 applies adownlink gain of −19 dB to each carrier signal 402 a-d. Row 408 depictsthe power level per carrier signal as transmitted by remote unit 106when there is no traffic load on carrier signal 402 a. Carrier signal402 a can be transmitted at a power level of 14 dBm, while carriersignals 402 b-d may be transmitted at power levels of 24 dBm. Withoutany optimization of the RAN and DAS, the remote unit 106 can continue toapply a downlink gain of −19 dB to each carrier signal 402 a-d. Row 410depicts the power level per carrier signal as transmitted by remote unit106 after the joint RAN-DAS-SON entity 108 optimizes the RAN and DAS byboosting the power levels of downlink carrier signals with a minimumtraffic load. Due to the low traffic conditions of carrier signal 402 a,the excess downlink power can be re-distributed and applied to carriersignals 402 b-d. The joint RAN-DAS-SON entity 108 can calculate a 1 dBgain boost for each of the carrier signals 402 b-d. Upon applying theboosting factor, while carrier signal 402 a (with no traffic load) istransmitted at a power level of 14 dBm (−19 dB gain), power levels ofcarrier signals 402 b-d can each increase to 25 dBm (−18 dB gain). Thecomposite power of the remote unit 106 remains constant.

In some aspects, the joint RAN-DAS-SON entity 108 can receive thetraffic load information on each downlink carrier signal and optimizethe transmission power levels of remote units based on the traffic loadinformation. For example, the joint RAN-DAS-SON entity 108 can receivetraffic load information as part of RAN O&M parameters received from RANnodes 118 a-d, 120 a-d. One non-limiting example of traffic loadinformation is information indicating the number of user devicesconnected to and in communication with RAN nodes 118 a-d, 120 a-d.Another example of traffic load information is information indicatingthe amount of bandwidth of the total signal bandwidth used by userdevices connected to and in communication with RAN nodes 118 a-d, 120a-d. The DAS head-end unit 102 can also receive traffic load informationfrom the RAN nodes 118 a-d, 120 a-d and provide the traffic loadinformation to the joint RAN-DAS-SON entity 108 as part of DAS O&Mparameters. The DAS head-end unit 102 can also measure the traffic loadinformation by demodulating each received downlink signal from RAN nodes118 a-d, 120 a-d and provide the traffic load information to the jointRAN-DAS-SON entity 108.

The traffic load information can indicate to the joint RAN-DAS-SONentity 108 the traffic load on each downlink carrier from RAN nodes 118a-d, 120 a-d. Based on the traffic load information, the jointRAN-DAS-SON entity 108 can determine target operations and managementparameters for optimizing the RAN and DAS by re-allocating excess signalpower to other downlink carriers. For example, for any downlink carriersignal that has a traffic load less than a predefined threshold, thejoint RAN-DAS-SON entity 108 can calculate the power headroom availablefor the carrier signal (e.g., the amount of allocated power that isunused due to the low load traffic conditions). The power headroom for agiven carrier signal can be the difference between the maximum possiblepower of a carrier signal and the actual power transmitted by a remoteunit 106 to provide wireless communication to connected user devices.

The joint RAN-DAS-SON entity 108 can allocate the measured powerheadroom available for the low threshold carrier signal to the othercarrier signals transmitted by the remote unit 106. For example, basedon the calculated power headroom, the joint RAN-DAS-SON entity 108 candetermine a boosting factor to apply to the carrier signals associatedwith traffic loads higher than the predefined threshold transmitted bythe remote unit 106. The boosting factor can include the amount ofdownlink gain to apply to each of the carrier signals with highertraffic load. In some aspects, target operations and managementparameters determined by the joint RAN-DAS-SON entity 108 can includethe boosting factor. The joint RAN-DAS-SON entity 108 can optimize theRAN and DAS by providing the boosting factor to the head-end unit 102.The head-end unit 102 can provide the boosting factor to the appropriateremote unit 106, which can amplify the downlink gain associated with thecarrier signals with higher traffic load according to the amount of theboosting factor. In other aspects, the joint RAN-DAS-SON entity 108 canoptimize the RAN and DAS by directly instructing the appropriate remoteunit 106 to amplify downlink gain associated with the carrier signalswith higher traffic load according to the amount of the boosting factor.

The foregoing description of the examples, including illustratedexamples, of the invention has been presented only for the purpose ofillustration and description and is not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Numerousmodifications, adaptations, and uses thereof can be apparent to thoseskilled in the art without departing from the scope of this invention.The illustrative examples described above are given to introduce thereader to the general subject matter discussed here and are not intendedto limit the scope of the disclosed concepts.

What is claimed is:
 1. A head-end unit of a distributed antenna system,comprising: an interface configured to communicate parameters with ajoint radio access network-distributed antenna system-self-optimizingnetwork (RAN-DAS-SON) entity, wherein the RAN-DAS-SON entity isconfigured to jointly optimize a radio access network and thedistributed antenna system; wherein the head-end unit is configured to:transmit a first set of parameters to the RAN-DAS-SON entity; receiveinstructions regarding target parameters from the RAN-DAS-SON entity;and adjust one or more configuration settings of at least one node ofthe distributed antenna based on the instructions regarding targetparameters from the RAN-DAS-SON entity.
 2. The head-end unit of claim 1,wherein the head-end unit is configured to adjust at least one of anuplink gain or a downlink gain of the head-end unit based on theinstructions regarding target parameters from the RAN-DAS-SON entity. 3.The head-end unit of claim 1, wherein the head-end unit is configured toadjust a simulcast factor of the distributed antenna system based on theinstructions regarding target parameters from the RAN-DAS-SON entity. 4.The head-end unit of claim 1, wherein the head-end unit is configured toadjust an output power level of one or more remote units the distributedantenna system based on the instructions regarding target parametersfrom the RAN-DAS-SON entity.
 5. The head-end unit of claim 1, whereinthe RAN-DAS-SON entity is included within the head-end unit.
 6. Thehead-end unit of claim 5, wherein the RAN-DAS-SON entity comprises: afirst interface configured to receive parameters from one or more nodesof the radio access network; a second interface configured to receivethe parameters from the head-end unit of the distributed antenna system;and a circuit configured to determine target parameters for the radioaccess network and the distributed antenna system and jointly optimizethe radio access network and the distributed antenna system based on theparameters from one or more nodes of the radio access network, theparameters from the head-end unit of the distributed antenna system, andthe target parameters.
 7. The head-end unit of claim 6, wherein thecircuit is configured to determine target parameters by determiningoptimal configuration settings for meeting one or more key performanceindicators of the radio access network.
 8. The head-end unit of claim 6,wherein the circuit is configured to jointly optimize the radio accessnetwork and the distributed antenna system by optimizing coveragecharacteristics, capacity characteristics, or performancecharacteristics of the radio access network and the distributed antennasystem.
 9. The head-end unit of claim 6, wherein the RAN-DAS-SON entityfurther comprises an element management system/network management system(EMS/NMS) interface configured to: forward the parameters from one ormore nodes of the radio access network and the parameters from thehead-end unit of the distributed antenna system to an EMS/NMS entity;and forward instructions received from the EMS/NMS entity to the one ormore nodes of the radio access network and the head-end unit of thedistributed antenna system.
 10. The head-end unit of claim 9, whereinthe instructions from the EMS/NMS entity include optimal optimizationsettings determined by the EMS/NMS entity.
 11. A radio access network(RAN) node, comprising: an interface configured to communicateparameters with a joint radio access network-distributed antennasystem-self-optimizing network (RAN-DAS-SON) entity, wherein theRAN-DAS-SON entity is configured to provide instructions regardingtarget parameters to jointly optimize the radio access network and adistributed antenna system; wherein the RAN node is configured to:transmit a first set of parameters to the RAN-DAS-SON entity; receivethe instructions regarding target parameters from the RAN-DAS-SONentity; and adjust one or more configuration settings of the RAN nodebased on the instructions regarding target parameters from theRAN-DAS-SON entity.
 12. The RAN node of claim 11, wherein the parametersinclude information indicating traffic loads on downlink signalstransmitted by a remote unit of the distributed antenna system andwherein the target parameters include a boosting factor indicating anamount of gain to apply to the downlink signals transmitted by theremote unit of the distributed antenna system.
 13. The RAN node of claim11, wherein the RAN node is configured to adjust an uplink gain of a lownoise amplifier of the RAN node based on the instructions regardingtarget parameters from the RAN-DAS-SON entity.
 14. The RAN node of claim11, wherein the RAN node is configured to adjust an uplink gain of atower mounted amplifier of the RAN node based on the instructionsregarding target parameters from the RAN-DAS-SON entity.
 15. The RANnode of claim 11, wherein the RAN node is configured to adjust an outputpower level of the RAN node based on the instructions regarding targetparameters from the RAN-DAS-SON entity.
 16. The RAN node of claim 11,wherein the RAN-DAS-SON entity is included within the RAN node.
 17. TheRAN node of claim 16, wherein the RAN-DAS-SON entity comprises: a firstinterface configured to receive parameters from one or more nodes of theradio access network; a second interface configured to receive theparameters from the head-end unit of the distributed antenna system; anda circuit configured to determine target parameters for the radio accessnetwork and the distributed antenna system and jointly optimize theradio access network and the distributed antenna system based on theparameters from one or more nodes of the radio access network, theparameters from the head-end unit of the distributed antenna system, andthe target parameters.
 18. The RAN node of claim 17, wherein the circuitis configured to determine target parameters by determining optimalconfiguration settings for meeting one or more key performanceindicators of the radio access network.
 19. The RAN node of claim 18,wherein the circuit is configured to jointly optimize the radio accessnetwork and the distributed antenna system by optimizing coveragecharacteristics, capacity characteristics, or performancecharacteristics of the radio access network and the distributed antennasystem.
 20. The RAN node of claim 18, wherein the RAN-DAS-SON entityfurther comprises a element management system/network management system(EMS/NMS) interface configured to: forward the parameters from one ormore nodes of the radio access network, the parameters from the head-endunit of the distributed antenna system to an EMS/NMS entity; and forwardinstructions received from the EMS/NMS entity to the one or more nodesof the radio access network and the head-end unit of the distributedantenna system.